Automated work-piece handling system for machine tool

ABSTRACT

An automated workpiece handling system for use with a machine tool having a plurality of workstations spaced along a longitudinally movable, elongate workpiece comprising a first cart for transporting workpieces to one end of the tooling machine, adjacent a first workstation, a first feeder mechanism on the machine tool for drawing workpieces from the first cart and delivering the workpieces onto the worktable, a mechanism on the worktable including the worktable itself for moving the workpieces along the worktable from a position adjacent the first workstation to a position adjacent a final workstation, a second cart for transporting workpieces from the other end of the machine tool, adjacent the final workstation, and a second feeder mechanism on the machine tool for drawing workpieces from the worktable and delivering the workpieces onto the second cart.

This is a continuation of copending application Ser. No. 773,502, filedon Sept. 4, 1985, now abandoned, which in turn is a continuation of Ser.No. 470,457, filed Feb. 28, 1983, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an automated workpiece handling systemfor a machine tool and, more particularly, to a method and apparatus fortransporting workpieces to, feeding workpieces onto, conveyingworkpieces along, feeding workpieces off of, and transporting workpiecesfrom a machine tool.

2. Description of the Prior Art

Automated machinery is often used to perform a variety of operations ona workpiece, such as drilling and/or routing. A modern automated machinetool typically includes a plurality of workstations spaced along amovable worktable, with each of the workstations having an alignmentdevice and a drilling and/or routing mechanism. The alignment devicealigns and secures a workpiece, such as a group of printed circuitboards, to the worktable so that the drilling and/or routing operationcan take place.

Previously, the workpieces have been inserted onto the alignment deviceof the individual workstations by hand. The machine tool then performs aprogrammed series of operations on the workpieces and the workpieces aremanually removed upon completion of these operations. Thus, a typicalautomated machine tool requires the constant attention of a humanoperator.

The manual insertion and removal of workpieces from an automated machinetool is tedious work and can result in inefficient operation of themachine. Human labor is relatively expensive and should therefore beused for tasks which can best utilize the talents that a human operatorhas to offer. Furthermore, the manual handling of the workpieces canadversely affect the output efficiency of the machine because of thespeed of the operator.

For some time, it has been recognized that a highly practical machinetool should have a fast, efficient system for bringing the workpieces tothe workstations and for removing the workpieces after the operationsare completed. It has been further recognized that such a system shouldoperate in a relatively economical manner and should preferably notrequire any human labor. One attempt to provide an automated handlingsystem for a machine tool is described and claimed in my copendingapplication Ser. No. 236,844, filed Feb. 23, 1981, and entitled HandlingSystem for an Automated Tooling Machine. Such handling systemincorporates a transporter which carries the workpieces to theworkstation of an automated tooling machine. The transporterincorporates a mechanism for feeding the workpieces onto the worktableat a selected workstation. The machine tool then incorporates amechanism for carrying the workpieces from station to station.

The system of my copending application is relatively complex and sincethe loading mechanism is part of the transport means, the loadingmechanism must be duplicated for each transport means and the transportmeans is complex and expensive. The conveyor belt system for moving theworkpieces from station to station is also complex.

SUMMARY OF THE INVENTION

According to the present invention, there is provided an automatedworkpiece handling system for use with a machine tool which trulysimplifies the process of transporting workpieces to and from, loadingworkpieces onto and off of, and moving workpieces along a machine tool.The present workpiece handling system is highly practical and is fastand efficient. The present workpiece handling system can operateeconomically without the intervention of any human labor.

Like the workpiece handling system of my copending application, thepresent workpiece handling system incorporates a cart for transportingworkpieces to and from a machine tool. On the other hand, the presentcart is a simple structure, having no loading equipment associatedtherewith. Because the cart is simple and light, many carts can be madeat a low cost and the carts can be automatically transported to themachine tool. The loading and unloading mechanism is part of the machinetool so that it need not be duplicated. Furthermore, the mechanism formoving the workpieces along the machine tool partially uses theworktable itself so that the system for conveying the workpieces fromstation to station is also simple.

Briefly, the present automated workpiece handling system for use with amachine tool having a plurality of workstations spaced along alongitudinally movable, elongate worktable comprises a first cart fortransporting workpieces to one end of the machine tool, adjacent a firstworkstation, a first feeder mechanism on the machine tool for drawingworkpieces from the first cart and delivering the workpieces onto theworktable, a mechanism on the worktable, including the worktable itself,for moving the workpieces along the worktable from a position adjacentthe first workstation to a position adjacent a final workstation, asecond cart for transporting workpieces from the other end of themachine tool, adjacent the final workstation, and a second feedermechanism on the machine tool for drawing workpieces from the worktableand delivering the workpieces onto the second cart.

OBJECTS, FEATURES AND ADVANTAGES

It is therefore the object of the present invention to solve theproblems associated with automating the process of delivering workpiecesto and receiving workpieces from a machine tool. It is a feature of thepresent invention to solve these problems by providing an automatedworkpiece handling system for use with a machine tool. An advantage tobe derived is a highly practical, automated machine. A further advantageis a fast and efficient system for bringing workpieces to theworkstations of a machine tool and removing the workpieces after theoperations are completed. A still further advantage is an automatedworkpiece handling system for a machine tool which does not require theintervention of a human operator.

Still other objects, features and attendant advantages of the presentinvention will become apparent to those skilled in the art from areading of the following detailed description of the preferredembodiment constructed in accordance therewith, taken in conjunctionwith the accompanying drawings wherein like numerals designate like orcorresponding parts in the several figures and wherein:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a machine tool incorporating the presentautomated workpiece handling system;

FIG. 2 is a front elevation view of the machine tool and automatedworkpiece handling system of FIG. 1;

FIG. 3 is a perspective view of a cart which is part of the workpiecehandling system of FIG. 1;

FIG. 4 is an enlarged sectional view taken along the line 4--4 in FIG.2;

FIG. 5 is a sectional view taken along the line 5--5 in FIG. 4;

FIG. 6 is a top plan view of the worktable of the machine tool of FIG.1;

FIGS. 7 and 8 are sectional views taken along the line 7--7 in FIG. 6and showing the operation of the workpiece elevating and lowering rails;

FIGS. 9a, 9b and 9c are a series of simplified diagrams showing theloading of workpieces onto the worktable; and

FIGS. 10a, 10b and 10c are a similar series of simplified diagramsshowing the unloading of workpieces from the worktable.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings and, more particularly, to FIGS. 1 and 2thereof, there is shown a machine tool, generally designated 10, whichhas been modified to incorporate a workpiece handling system, generallydesignated 20, constructed in accordance with the teachings of thepresent invention. Because machine tool 10 is generally a conventionaldrilling/routing machine, only those portions thereof necessary for anunderstanding of workpiece handling system 20 will be described. Machinetool 10 is of the type having a plurality of workstations 11, each ofwhich has a drilling or routing mechanism 12 positioned over a largeworktable 13. A workpiece 15, which may consist of a stack of printedcircuit boards, may be placed under each mechanism 12 on worktable 13. Acontrol console (not shown), which usually contains a minicomputer, istypically programmed with a set of instructions for directing machinetool 10 to perform a series of drilling or routing operations onworkpieces 15.

In a typical embodiment of a machine tool, and the embodimentincorporated herein, worktable 13, under the control of the controlconsole, is movable longitudinally and the overhead assembly 14 on whichmechanisms 12 are mounted is movable laterally to perform the necessarydrilling and/or routing operations. In addition, the individualmechanisms 12 are movable in a direction perpendicular to worktable 13.In this manner, the workpieces 15 at the various workstations 11 may besimultaneously drilled and/or routed by mechanisms 12. After themachining operation is completed, the drills or routing tools arewithdrawn from workpieces 15 and they may be removed from worktable 13.Machine tool 10 includes suitable drive means (not shown) for permittingthe beforementioned longitudinal movement of worktable 13, lateralmovement of overhead assembly 14, and the vertical movement ofmechanisms 12. Suitable support structure is also provided, a discussionof which is not here considered relevant.

As mentioned previously, in prior automated machine tools, workpieceshave been placed at the workstations by hand. After all of the machiningoperations were completed, the workpieces were also removed by hand. Inorder to eliminate the need for manual loading and unloading of theworkpieces, workpiece handling system 20 has been added to machine tool10.

Referring now to FIGS. 1-5, workpiece handling system 20 includes aplurality of transport means or carts 21. Carts 21 may be made fromaluminum or other suitable metal material and include a generallyrectangular frame comprising upright members 22a-22d, a base 23 and atop 24, base 23 including a plurality of wheels 25 so that cart 21 maybe readily moved into and out of contact with machine tool 10. A firstseries of brackets 26 are connected between upright members 22b and 22cand a second series of brackets 27 are connected between upright members22a and 22d, brackets 26 and 27 defining a plurality of verticallyarranged shelves for supporting workpieces 15.

As described more fully in my copending application, the raw workpiecesmay be unmachined printed circuit boards which are stacked or grouped ingroups of three or more, with each group secured together by alignmentpins (not shown) which pass through the group of boards and protrudebelow the bottom board of each group. The groups of printed circuitboards (each group hereinafter referred to as a workpiece 15) are placedin a large stack vertically on the individual shelves. Brackets 26include two parallel, spaced rails which receive one of the alignmentpins, for location purposes, and the other alignment pin is supported bybrackets 27. Bracket 27 is formed so as to receive workpieces 15 havingdifferent widths. Upright members 22a-22d each have a pair of L-shapedbrackets 28 connected thereto in vertically spaced alignment, brackets28 being connected to the individual upright members with the samevertical spacing.

Workpiece handling system 20 includes an elevator mechanism, generallydesignated 30, at each end of machine tool 10. Since the elevatormechanisms 30 at the opposite ends of machine tool 10 are identical,only the one at the left end of machine tool 10, designated 30a, whichis used for feeding workpieces 15 onto worktable 13, will be described.

Elevator mechanism 30a includes a pair of opposed, vertically oriented,U-shaped channel members 31 which are positioned in parallel, spacedrelationship, with the open sides of the channels facing each other.Each channel 31 supports, for vertical movement, a plate 32 which ispositioned adjacent the open end of each channel 31. Plate 32 supportsthe ends of a plurality of shafts 33 on which rollers 34 are mounted forrotation, rollers 34 engaging tracks 35 secured to the open ends ofchannels 31. Tracks 35 may be connected to channels 31 by bolts 36. Withsuch a construction, plates 32 are free to ride in a vertical directionalong tracks 35.

Each plate 32 has secured thereto, on the inside surface thereof, at thetop and bottom thereof, a pair of support blocks 37, which may be weldedto plate 32. Each block 37, has connected thereto, by means of bolts 38,a disc 39 having an internally threaded hole 40. Support blocks 37 havealigned non-threaded holes 41. A threaded shaft 42 extends verticallywithin each channel 31, each shaft 42 engaging the upper and lower discs39 of the associated plate 32. It should be evident that rotation ofshafts 42 cause plates 32 to be driven upwardly and downwardly relativeto channels 31.

The upper ends of the two shafts 42 of each elevator mechanism 30terminate in mechanisms 43 where they are interconnected forsimultaneous rotation by a shaft 44 driven by a motor 45 connected toone of mechanisms 43. In this manner, a single motor 45 drives theopposite plates 32 for simultaneous vertical movement. Each plate 32 hasconnected thereto, in vertically spaced relationship, a bracket 46 whichsupports an upwardly projecting pin 47. Brackets 46 may be connected toplates 32 by means of bolts 48. The spacing between brackets 46 is thesame as the spacing between brackets 28 and brackets 28 have holes 29therein for receipt of pins 47. Pins 47 may be partially surrounded byrubber washers 49.

In operation, it is seen that with plates 32 in their lowermostpositions, a cart 21a may be moved into close proximity to machine tool10 until upright members 22c and 22d are between the opposed plates 32.At this time, pins 47 would be in positions lower than brackets 28 andcart 21a can be wheeled forwardly until upright members 22c and 22dactually come into contact with brackets 46. At this time, motor 45 canbe activated to drive plates 32 upwardly. As plates 32 move upwardly,the four pins 47 enter the four holes 29 in brackets 28, engaging same.Continued upward movement of plates 32 continues the upward movement ofcart 21a therewith, for reasons which will appear more fullyhereinafter. Suffice it to say that workpiece handling system 20 removesworkpieces 15 from cart 20, one at a time, starting with the topmostworkpiece 15.

As shown most clearly in FIGS. 1 and 2, an identical elevator mechanism30b is connected to the opposite end of machine tool 10. While cart 21aat the lefthand side of machine tool 10 is shown in its lowermostposition, the cart 21b at the other end of machine tool 10 is shown inits uppermost position. As will be described more fully hereinafter,workpiece handling system 20 removes workpieces 15 from worktable 13 anddelivers them into cart 21b, filling the individual shelves of cart 21bfrom the bottom thereof. As workpieces 15 are removed from cart 21a, thecart 21a is driven upwardly. As workpieces 15 are delivered to the cart21b, cart 21b is driven downwardly.

Workpieces 15 are drawn from cart 21a and delivered onto worktable 13and are drawn from worktable 13 and delivered to cart 21b by identicalfeed mechanisms 50a and 50b. Feed mechanism 50a includes a hydrauliccylinder 51 having an internal piston (not shown) connected to a movablemember 52 having connected thereto a ram 53. Ram 53 has the end thereofconnected to a bracket 54 which engages the edge of workpieces 15. Uponactivation of cylinder 51, member 52 is driven to the opposite endthereof whereupon bracket 54 engages a workpiece 15 and slides it eitheronto worktable 13 or off of worktable 13, as the case may be. Theworkpiece 15 at the top of the stack of cart 21a is considered to be atthe "feed position" and is pushed by ram 53 onto worktable 13. Amicroswitch 55 may be positioned to sense the uppermost workpiece 15 aselevator mechanism 30a elevates the topmost workpiece 15 to the feedposition.

It can therefore been seen that carts 21 are relatively simple membersand that elevator mechanisms 30, in conjunction with feed mechanisms 50,both of which are permanent parts of machine tool 10, are fullyoperational in delivering workpieces 15 onto one end of machine tool 10,adjacent the first workstation, designated 11a, and for removingworkpieces 15 from the other end of machine tool 10, adjacent the lastworkstation, designated 11d. All that remains to be described is anautomatic mechanism for conveying each workpiece 15 along worktable 13,from workstation 11a, past the intermediate workstations, designated 11band 11c, to workstation 11d.

Returning now to FIGS. 2, 6, 7 and 8, the mechanism for transportingworkpieces 15 along worktable 13 comprises a pair of elongate, parallel,spaced rails 60 which are mounted on machine tool 10, adjacent worktable13. More specifically, worktable 13 has a pair of elongate channels 16therein in which rails 60 are mounted. As will be explained more fullyhereinafter, rails 60 move longitudinally with worktable 13 and areadapted to be elevated or lowered for elevating workpieces 15 aboveworktable 13 or lowering workpieces 15 onto worktable 13. These twopositions of rails 60 are shown in FIGS. 7 and 8. It will be seen fromFIG. 7 that when in the lowered position, rails 60 are below worktable13 so that workpieces 15 rest on worktable 13. In the elevated positionof rails 60, as shown in FIG. 8, rails 60 are elevated above worktable13 in position to elevate workpieces 15.

More specifically, machine tool 10 includes a movable base 17 on whichworktable 13 and rails 60 are mounted. Mounted on base 17 are aplurality of support blocks 61. An L-shaped linkage 62 is supported forrotation by each block 61 by means of a pin 63 which extends through acentral portion of linkage 62 and into block 61. Each linkage 62includes a pair of legs 62a and 62b. The free ends of all of legs 62bare interconnected by means of a rod 64 and suitable connectors 65 whichconnect legs 62b to rod 64. The free ends of legs 62a have slots 66therein through which extend pins 67. Pins 67 are connected to brackets68 which are connected to rails 60.

A hydraulic cylinder 70 having input and output lines 71 and 72 isconnected to one end of base 17, directly below one of the brackets 68a.Cylinder 70 drives a piston 73 which has a U-shaped bracket 74 connectedto the end thereof, bracket 74 surrounding bracket 68a.

In the operation of rails 60, it should be evident from an inspection ofFIGS. 7 and 8 that activation of cylinder 70 to drive pistons 73outwardly to the position shown in FIG. 8 drives rails 60 upwardly,causing clockwise rotation of the first linkage 62. Rotation of thefirst linkage 62 causes simultaneous rotation of the remaining linkages62 by means of the interconnection provided by rod 64 and connectors 65.The simultaneous rotation of each of linkages 62 causes elevation of thefree ends of leg 62a and the elevation of rails 60 connected thereto.Activation of cylinder 70 in the opposite direction, to the positionshown in FIG. 7, causes lowering of rail 60. While rails 60 could belowered by gravity, it is preferable to provide a direct connectionbetween pistons 73 and rails 60. Thus, the pins 67a which extend throughthe brackets 68a above pistons 73 also extend through brackets 74.

Referring to FIG. 2, the remaining element of the mechanism for movingworkpieces 15 along worktable 13 comprises a plurality of wiper blades75 which are connected to an overhead support member 18 of machine tool10. As will be explained more fully hereinafter, blades 75 extenddownwardly from support member 18 and extend laterally from one rail 60to the other. Blades 75 are positioned so that they almost contact theupper surfaces of rails 60 when rails 60 are in their elevatedpositions. The reason for this will appear more fully hereinafter.

As described more fully in my beforementioned copending application,each workstation 11 has an alignment device which aligns and clamps theworkpiece 15 at the workstation. This alignment device is not a portionof the present invention but will be described briefly in that it is anessential part of machine tool 10. A typical alignment device, generallydesignated 80, is shown in FIG. 6 and includes a stationary bar 81mounted within a cavity 82 in worktable 13 and a bar 81a mounted withina cavity 82a in worktable 13 such that the top surfaces of bars 81 and81a are flush with the top surface of worktable 13. Opposing bars 81 and81a are movable bars 83 and 83a, respectively. Bars 83 and 83a arespaced from bars 81 and 81a, respectively, to form alignment slots 84and 84a, respectively, therebetween. Bar 81a has a notch 85a thereinwhich defines an alignment hole 86a between bars 81a and 83a. Alignmenthole 86a is adapted to receive one of the alignment pins of a workpiece15 and alignment slot 84 is adapted to receive another alignment pin.

As is well known in the art, before the alignment pins of the workpieces15 are inserted into the alignment hole 86a and alignment slot 84, bars83 and 83a are moved away from bars 81 and 81a, respectively, to an openposition. The workpiece 15 is lowered by rails 60 onto the surface ofworktable 13 so that the alignment pins are between bars 81 and 83 and81a and 83a, respectively. Bars 83 and 83a are then moved back towardbars 81 and 81a, respectively, to a closed position with the alignmentpins clamped between bars 81 and 83 and within the alignment hole 86a.In this manner, the workpieces 15 are aligned and secured relative toworktable 13. The movable bars 83 and 83a may be moved into their openand closed positions by suitable hydraulic mechanisms (not shown) wellknown to those skilled in the art.

The operation of workpiece handling system 20 for drawing workpieces 15from cart 21a and delivering workpieces 15 onto worktable 13 and forsubsequently transporting workpieces 15 from workstation 11a toworkstation 11b, then to workstation 11c, and then to workstation 11d,can best be understood with reference to FIGS. 9a through 9c.Subsequently, the manner in which workpieces 15 may simultaneously bedelivered from workstation 11d onto cart 21b will be described withreference to FIGS. 10a through 10c.

Referring first to FIG. 9a, it will be understood that throughconventional means (not shown), worktable 13, base 18 and rails 60 havethe capability of being moved longitudinally by an amount equal to thespacing between workstations 11. When it is initially desired to delivera workpiece 15 from cart 21a onto worktable 13, worktable 13 is moved toits extreme left position, rails 60 are elevated and ram 53 of feedmechanism 50a is also moved to its extreme left position, all of thesepositions being shown in solid lines in FIG. 9a. Elevator mechanism 30ais activated to drive cart 21a upwardly until the uppermost workpiece 15contacts switch 55. At this time, cylinder 51 is activated and ram 53 isdriven to its rightmost position, shown in phantom in FIG. 9a, movingthe uppermost workpiece 15 onto elevated rails 60.

At this time, rails 60 are lowered to deposit workpiece 15 ontoworktable 13, at a delivery position to the left of workstation 11a.These positions of worktable 13 and rails 60 are shown in solid lines inFIG. 9b. At this time, worktable 13 is driven to its rightmost position,as shown in phantom in FIG. 9b. Workpiece 15 moves with worktable 13,below the first wiper blade 75a. The new position of workpiece 15 isalso shown in phantom in FIG. 9b.

At this time, rails 60 are elevated, elevating workpieces 15 aboveworktable 13. This position of worktable 13 and rails 60 is shown insolid lines in FIG. 9c. At this time, worktable 13 is driven to itsextreme left position, rails 60 moving therewith, these positions ofworktable 13 and rails 60 being shown in phantom in FIG. 9c. It shouldbe apparent that since wiper blades 75 are now in the path of workpieces15, workpieces 15 are held stationary as worktable 13 and rails 60 move.Thus, workpiece 15 remains at a position between workstation 11a andworkstation 11b.

It will be immediately apparent that worktable 13 and rails 60 have nowreturned to their initial positions, as shown in solid lines in FIG. 9a.In this position, another workpiece 15 can be delivered onto rails 60and worktable 13. This procedure can now be repeated until fourworkpieces 15 have been loaded onto worktable 13 and shifted toworkstations 11a, 11b, 11c, and 11d. It should be particularly notedthat the shifting of workpieces 15 is done entirely by worktable 13 andno separate conveying assembly is required.

At this time, drilling or routing mechanisms 12 may be activated toperform whatever work operation is required on workpieces 15. When it istime to remove workpieces 15 from worktable 13 and load new workpieces15 onto worktable 13, worktable 13 is moved to its extreme rightposition and rails 60 are elevated, as shown in solid lines in FIG. 10a.Elevator mechanism 30b is activated to lower cart 21b to a positionwhere the uppermost empty shelf is in its receive position. The cylinder51 associated with feed mechanism 50b may then be activated to drive theassociated ram 53 to the right, to the position shown in phantom in FIG.10a. In this position, the ram 53 drives the workpiece 15 into cart 21b.

With rails 60 still elevated, as shown in solid lines in FIG. 10b,worktable 13 is driven to the left, rails 60 moving therewith, to theposition shown in phantom in FIG. 10b. Recall that under thesecircumstances, which are also shown in FIG. 9c, the workpieces 15 areheld stationary by wiper blades 75 so that after a time, theseworkpieces are also shifted one position to the right. A new workpiece15 may now be loaded onto worktable 13, as described previously withregard to FIG. 9a. Then, rails 60 may be lowered and worktable 13 movedto the right, from the positions shown in solid lines in FIGS. 9b and10c to the positions shown in phantom in these same figures. At thistime, rails 60 may be elevated to the positions shown in solid lines inFIG. 10a and the next workpiece 15 removed from worktable 13. Thisprocedure may be repeated four times so that the four workpieces thathave been previously drilled or routed are removed from worktable 13while four new workpieces 15 are simultaneously moved onto worktable 13.

It can therefore be seen that according to the present invention, thereis provided an automated workpiece handling system 20 for use with amachine tool 10 which truly simplifies the process of transportingworkpieces 15 to and from, loading workpieces 15 onto and off of, andmoving workpieces 15 along machine tool 10. Workpiece handling system 20is highly practical and is fast and efficient. Workpiece handling system20 can operate economically, without the intervention of any humanlabor.

Like the workpiece handling system of my copending application,workpiece handling system 20 incorporates a cart for transportingworkpieces 15 to a machine tool. On the other hand, cart 21 is a highlysimple structure, having no loading equipment associated therewith.Because cart 21 is simple and light, many carts 21 can be made at a lowcost and carts 21 can even be automatically transported to machine tool10. The loading/unloading mechanism is a permanent part of machine tool10 so that it need not be duplicated. Furthermore, the mechanism formoving workpieces 15 along machine tool 10 partially uses worktable 13itself so that the system for conveying workpieces 15 from station tostation is highly simple.

While the invention has been described with respect to the preferredphysical embodiment constructed in accordance therewith, it will beapparent to those skilled in the art that various modifications andimprovements may be made without departing from the scope and spirit ofthe invention. Accordingly, it is to be understood that the invention isnot to be limited by the specific illustrative embodiment, but only bythe scope of the appended claims.

I claim:
 1. An automated machine tool system comprising:a machine toolhaving a plurality of workstations spaced along a longitudinally movableworktable, wherein automated machining operations are performed onworkpieces at each workstation; first transport means for transportingworkpieces to one end of said machine tool, adjacent a firstworkstation; first feeder means on said machine tool for (a) engagingworkpieces on the first transport means, (b) drawing workpieces fromsaid first transport means and delivering said workpieces onto saidworktable, and (c) disengaging the workpieces after delivery to theworktable; means for facilitating the shifting of workpieces todifferent workstations along the worktable, said means including meansfor maintaining the workpieces stationary while the worktable is movedin a first longitudinal direction thereby to shift each workpiece to anadjacent workstation; means for selectively elevating workpieces abovesaid worktable and lowering workpieces onto said worktable; and meansconnected to said machine tool for engaging said workpieces whenelevated above said worktable for preventing movement of said workpieceswith said worktable as said worktable moves longitudinally wherebymovement of said worktable with said workpieces elevated shifts saidworkpieces along said worktable.
 2. A system according to claim 1,wherein said means for selectively elevating and lowering workpiecescomprises:a pair of elongate, parallel, spaced rails mounted on saidmachine tool, adjacent said worktable; and means for selectivelyelevating and lowering said rails.
 3. A system according to claim 2,wherein said workpieces engaging means comprises:a plurality of bladesconnected to said machine tool and extending downwardly, transverse tosaid worktable to a position in the path of said workpieces when saidworkpieces are elevated above said worktable.
 4. A system according toclaim 1, wherein said workpieces engaging means comprises:a plurality ofblades connected to said machine tool and extending downwardly,transverse to said worktable to a position in the path of saidworkpieces when said workpieces are elevated above said worktable.
 5. Asystem according to claim 1, further comprising:second transport meansfor transporting workpieces from the other end of said machine tool,adjacent a final workstation; and second feeder means on said machinetool for drawing workpieces from said worktable and delivering saidworkpieces onto said second transport means.
 6. A system according toclaim 5, wherein said second transport means is identical to said firsttransport means.
 7. A system according to claim 5, wherein said firstfeeder means comprises:a first positioning ram on said machine tool formoving workpieces from said first transport means onto said worktable.8. A system according to claim 7, wherein said second feeder meanscomprises:a second positioning ram on said machine tool for movingworkpieces from said worktable to said second transport means.
 9. Asystem according to claim 5, wherein each of said transport meanscomprises:a frame; a plurality of brackets connected to said frame andpositioned to define a plurality of vertically arranged shelves forsupporting workpieces; and connector means connected to said frame forpermitting the removable connection of said frame to said worktable. 10.A system according to claim 9, further comprising:first elevator meansconnected to said machine tool for engaging said connector means of saidfirst transport means; and first drive means for vertically driving saidfirst elevator means so as to elevate said first transport means tobring each of said shelves thereof sequentially to a feed position wheresaid first feeder means draws the workpiece on said shelf at said feedposition from said first transport means and delivers said workpieceonto said worktable.
 11. A system according to claim 10, furthercomprising:second elevator means connected to said machine tool forengaging said connector means of said second transport means; and seconddrive means for vertically driving said second elevator means so as toelevate said second transport means to bring each of said shelvesthereof sequentially to a receiving position where said second feedermeans draws a workpiece from said worktable and delivers said workpieceonto said shelf at said receiving position of second transport means.12. A system according to claim 11, wherein said first feeder meanscomprises:a first positioning ram on said machine tool for movingworkpieces at said feed position of said first transport means to saidworktable.
 13. A system according to claim 12, wherein said secondfeeder comprises:a second positioning ram on said machine tool formoving workpieces from said worktable onto said second transport means.